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Re: The energy



What should be added at this point is: mass is also an abstraction.

Mass is a physical concept, matter a philosophical one.
Both are abstractions, but of quite a different kind.
Also, the questions:
a. what is mass?
b. what is matter?
are very different. I don't think we, as physicists, are entitled to
answer to b. We take matter as a fact of life, and go on to study how
it behaves in different condition, e. g. at very high velocities.
Maybe I am wrong on this, but I am pretty sure that you cannot speak
correctly on this matter if you identify matter and mass.

Paolo

P.S. Please, forgive my poor English.

----- Original Message -----
From: "Leigh Palmer" <palmer@SFU.CA>
To: <PHYS-L@LISTS.NAU.EDU>
Sent: Tuesday, October 19, 2004 9:16 PM
Subject: The energy


On 18-Oct-04 Michael Edmiston wrote:

Since Jim asks about e = mc^2 it would be reasonable to assume he will
read my first post on "mass" and then ask me "what is material" or
"what
is matter."

I usually answer that question by saying matter is "bound energy" or by
saying it is "localized energy."

I suppose that will bring the question "what is energy." The only
response I have to that is... energy is what the universe is made of.

I have great respect for Michael's grasp of physics, but it is my
judgment that in holding this opinion he commits a heresy, and by
teaching it to his students he commits a venial sin.

(Please forgive the metaphor, coming as it does from an atheist, but it
happens that it is apt in this case.)

The orthodox view, which I hold to be correct: The energy is not
substantial; it is not a real entity. The energy is an abstraction. The
energy did not exist before it was invented. The energy is a state
function, a quantity which may be calculated for any isolated physical
system from the values of all the parameters that characterize its
state.